teacher Professor Ernst-Joachim Ivers to whom I still owe many insights 20 years after the end of his working life. This English edition is not an unedited translation of the German edition of 1990. The text has been substantially revised in some chapters, taking into account the literature published in the mean time. I wish to thank Dr.-Ing. H. Finken, Freiberg, who has prepared the translation from German into English with deep scientific understanding and in close contact with the author. I also wish to express my gratitude to Chapman & Hall for their support to this project without which the English edition could not have been published. Dr.-Ing. habil. C. Bernhardt Freiberg 1 Position, tasks and structure of particle size analysis Today the concept of particle size analysis is that of a special field of particle measurement technology, which in turn is part of particulate technology. This classification has developed over the last 20 years; it is the result of a scientific integration process taking place in many industrialized countries of the world. In recent years, the meaning and mutual connection of the related concepts as well as the tasks of the scientific disciplines designated by them have been the subject of intensive discussion which, however, has not led to a generally accepted terminology.